Measuring and control apparatus

ABSTRACT

For controlling the processing of strip metal in for example a rolling mill, apparatus is provided ahead of the press to derive a signal in dependence on the thickness and hardness of the strip, this signal being used to control the rolling mill. The apparatus comprises two measuring heads which bear on the two sides of the strip with pressures sufficient to deform the material of the strip.

I United States Patent 1 3,665,743 F rohling May 30, 1972 54] MEASURING AND CONTROL 3,526,114 9/ 970 Wistreich ..72/9 APPARATUS 3,194,036 7/1965 Canfor et a1. ..72/11 3,368,381 2/1968 Frohling eta1.. ....72/ 245 X [72] Inventor: Josef Frohling, Konigshergerstrasse, Olpe, 1,814,354 7/1931 Webster et al.. ..72/ 16 Germany 2,275,509 3/ 1 942 Dahlstrom ..72/9 3,140,545 7/1964 Murt1and,'Jr.... .33/1431, X [22] 1969 3,162,069 12/1964 McLay et a1 ....72/205 x 21 Appl. No.: 859,342

Primary Examiner-Milton S. Mehr Attomey-Bums, Doane, Swecker & Mathis [30] Foreign Application Priority Data Sept. 23, 1969 Germany ..P 17 98 305.0

[57] ABSTRACT [52] 11.8. CI. ..72/11, 72/16, 324/34 TK; For controlling the processing f Strip metal in f example a 33/ M3 L rolling mill, apparatus is provided ahead of the press to derive 1 Int. a ignal in de endence on the thickness and hardness of [he 0 Search ..72/18, 8, 9, 12, 16, l trip this being used to control the rolling The ap- 4 143 L paratus comprises two measuring heads which bear on the two sides of the strip with pressures sufiicient to deform the [56] References Cited material of the strip.

UNITED STATES PATENTS 1,969,536 8/1934 Winne ..72/16 14 Claims, 4 Drawing Figures Patented May 30-, 1972 3,665,743

3 Sheets-Sheet 1 Patented May 30-, 1972 3 Sheds-Sheet z Patented May 30-, 1972 3,665,743

3 Sheets-Sheet 3 FIG. 4

ATTORNEYS MEASURING AND CONTROL APPARATUS BACKGROUND OF THE INVENTION Apparatus for measuring the thickness of a moving strip is known. Such apparatus may, for example, comprise two sensing rollers between which the moving strip is passed, the rollers being kept in constant contact with the top and bottom of the strip. Fluctuations in the thickness of the material passing through then result in corresponding fluctuations in the spacing between the rollers. These spacing fluctuations may be converted into control pulses, for example by electromagnetic means, by using light rays and photo-electric cells, or by using 'y-rays and the like; the control pulses then act through appropriate control members, for example, to adjust the relative positions of the work rolls in a rolling mill in which the strip material is undergoing a rolling process.

If such measuring means follow the rolling mill or other processing machine, the control applied to the machine no longer corresponds exactly to the required correction of the process. But even if the measuring means precedes the processing machine so that the control pulses are derived before processing takes place, the control process initiated by the pulses nevertheless takes place, the control process initiated by the pulses nevertheless take place too late, particularly if a number of cumbersomely operating machine parts have to be moved in order to put the control into effect.

Another drawback of known measuring and control apparatus is that it only enables the thickness of the material passing through to be measured and not the hardness thereof. This defect is felt particularly if the measuring and control apparatus has to be operated in conjunction with a rolling mill, for if the material is to be rolled to a uniform thickness, the roll pressure must be regulated in dependence on both the thickness and the hardness of the material to be rolled. Previous measuring apparatus has consequently proved a failure in connection with the control of rolling mills.

One object of the present invention, therefore, is to provide a measuring and control apparatus which will respond both to fluctuations in thickness and fluctuations in hardness of a strip material. Another object is to provide such apparatus for controlling a rolling mill, in dependence on both the thickness and the hardness of the material being processed.

SUMMARY OF THE INVENTION The subject matter of the invention is accordingly a measuring and control apparatus, the measuring pulses of which actuate a control member, located in a processing machine behind it for material passing through to be processed, to control the operation of the said machine. The apparatus according to the invention is characterized by two opposed measuring heads engaging the top and bottom of the material passing through to be processed, the heads being movable substantially perpendicularly to the direction in which the material is advanced and pressing against the material with a constant pressure sufficient to deform the latter.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 of the accompanying drawings illustrates, by way of example, a preferred embodiment of the apparatus according to the invention, combined in this special case with a rolling mill for strips of metal,

FIG. 2 of the accompanying drawings illustrates, also by way of example, a further embodiment.

FIG. 3 of the accompanying drawings illustrates a perspective view of a measuring head roller according to the invention.

FIG. 4 of the accompanying drawings illustrates schemati- Y DESCRIPTION OF THE PREFERRED EMBODIMENT The metal strip 1 to be rolled approaches the measuring apparatus C from the left, moves between the two measuring heads 2 and 2a in the direction of the arrow and then passes through the rolling mill R which follows. The measuring heads 2, 2a are connected to bars 3 and 3a, the outer ends of which carry pistons 5 and 5a movable within hydraulic cylinders 4 and 4a. The hydraulic pressure in the cylinders 4, 4a, exerted on the metal strip 1 by way of the bars 3, 3a and influence 2, 2a, is adjustable and has to be kept constant during the measuring and control process. The pressure exerted on the metal strip 1 need not be generated by hydraulic means and may be produced in any other suitable way. The essential factor is that the pressure should be large enough to deform the metal strip 1. If this requirement is met, the distance between the two measuring heads 2, 20 will vary according to the fluctuations in the thickness and hardness of the metal strip 1 passing through. The pressure is preferably adjusted in such a way that the metal strip 1 is deformed within its elastic range. It will be apparent that changes in thickness and hardness characteristics of the strip 1 influence the ability of the strip to impart a reactive force, i.e., counterpressure, against compressing agents, such as the measuring heads 6, 6a and the mill rolls 18. Since the heads 6, 6a are urged in the previously described manner to deform the strip, they will be movable in responsive to a change in such counterpressure.

The measuring heads 2, 2a may be in any desired form, although it is preferable for them to comprise rollers 6, 6a to engage the metal strip 1. It is an advantage for the rollers 6, 6a to have a cambered surface, that is to have a somewhat larger diameter in the center than at the edges as shown in FIG. 3.

The movements of the measuring heads 2, 2a resulting from the fluctuations in the thickness and hardness of the metal strip 1 are transmitted to the bars 3, 3a. The bars 3, 3a are made of magnetic material and surrounded by induction coils 7, 7a, in which the movement of the bars 3, 3a induces a current, the fluctuations of which correspond to the fluctuations in the thickness and hardness of the metal strip 1. These current fluctuations are, therefore, suitable pulses to control the operation of the rolling mill which follows.

The two induction coils 7, 7a are interconnected in such a way that the induced currents are added if the measuring heads 2, 2a move in opposite directions, but are differenced, and hence substantially cancel one another, if the heads 2, 2a move in the same direction. As the metal strip 1 moves from left to right (in FIG. 1), it is not always possible to prevent it from making certain upward or downward movements, which the measuring heads 2, 2a then follow. The effect of interconnecting the two coils 7, 7a as mentioned above is to prevent such movements of the metal strip 1 from giving rise to any undesired control pulses.

The control pulses induced in the coils 7 and 7a and corresponding to the fluctuations in the thickness and hardness of the metal strip 1 are supplied over a lead 8 to an electrical amplifier 9. Amplified pulses are supplied by the amplifier 9 over a lead 10 to control a hydraulic valve 11. This converts the electrical pulses into fluctuations in pressure, which are transmitted by pipes 12, 12a to hydraulic cylinders 13, 13a and pistons 14, 14a. A rack 15 connected to the pistons 14, 14a is thereby displaced, the displacement being transferred by a gear rim to a cam 16. The cam 16 controls the pressure with which a backing roll 17 of the rolling mill following the measuring and control apparatus presses onto the work roll 18 and the work roll onto the metal strip 1.

The use of an induction coil arrangement to convert the fluctuations in the thickness and hardness of the material passing through into measuring and control pulses is preferred, although not essential. The fluctuations may also be converted by means of light rays and photoelectric cells or with the aid of 'y-rays. Nor is it essential for the control pulses to act on a hydraulic system. They could, for example, be converted into mechanical movements to control any desired system. The hydraulic arrangement here described is, however, specially preferred, particularly in combination with a rolling mill, as the roll pressure is controlled by the pulse without any substantial movement of mechanical parts, such as the setting of levers, the engagement and disengagement of clutches, the starting of control motors and the like, and the system, therefore, operates with so little inertia that the roll pressure is always controlled by the pulse at the correct time.

The distance between the measuring heads 2, 2a and the control member located in the processing machine which follows is selected so that the time between the derivation of the measuring pulse and the controlling of the processing machine is adapted to the speed at which the material passes through. A time delay or relay may preferably be provided to compensate for fluctuations and variations in the speed of the moving material. I

If reversing machines, such as reversing rolling mills, are to be controlled by the apparatus according to the invention, the apparatus should have two measuring heads on each side of the machine controlled, as shown in the left-hand measuring apparatus C and the right-hand measuring apparatus C in FIG. 4 and the pulses should in each case be derived by the two measuring heads located before the point of entry of the material into the machine.

It is particularly advantageous to combine the control member of the apparatus according to the invention with the member regulating the roll pressure or roll gap of the rolling mill of a combined casting, rolling, milling and finishing plant. FIG. 2 of the accompanying drawings shows such a plant, in which the material B to be processed, emerging from the chiller A cast but with an irregular surface, passes through the advancing and planishing mill D controlled by the apparatus C according to the invention and through a milling machine E, and is then rolled up or fed to a finishing plant F.

The apparatus according to the invention makes it possible for the first time to measure not only the thickness but also the hardness of the material passing through and to utilize the measuring impulses obtained to control the operation of a processing machine which follows, particularly a rolling mill. lt is, therefore, now possible to produce rolled material of truly uniform thickness, which represents a considerable technical advance provided by the invention.

1 claim:

1. A measuring and working apparatus for moving strip material comprising:

a strip working means for working said strip material;

an adjusting means operatively connected to said strip working means to adjust the latter in accordance with strip characteristics;

a measuring head assembly positioned upstream of said strip working means for regulating the adjustment of said strip working means in response to fluctuations in the thickness and hardness characteristics of the strip material, said measuring head assembly comprising:

a pair of oppositely positioned measuring head means mounted to engage opposite surfaces of said strip material;

said measuring head means being mounted for displacement in a direction generally perpendicular to the direction of movement of said strip material;

pressure means for urging the measuring head means into engagement with said strip material with a force of a magnitude adequate to cause sufficient deformation of said strip material for sensing both thickness and hardness characteristics of said strip material;

said urged measuring head means being movable in response to a change in counterpressure exerted by said strip material resulting from sensed thickness and hardness characteristics thereof; and

control means operatively associated with said measuring head means and said adjusting means for operating said adjusting means in response to said displacement of said pressured measuring head means due to changes in said counterpressure produced by thickness fluctuations and hardness fluctuations of said strip material sensed by said measuring head means.

2. Apparatus according to claim 1 wherein the force exerted by said pressure means causes a deformation of said strip material within its elastic limit.

3. Apparatus according to claim 1 wherein said pressure means includes hydraulically operated means.

4. Apparatus according to claim 1 wherein each measuring head means includes a freely rotatable roller bearing against said strip material.

5. Apparatus according to claim 4 wherein the surfaces of said rollers are cambered.

6. Apparatus according to claim 1 wherein said control means comprises:

a bar of magnetic material connected to each measuring head means for transmitting said displacement of. each measuring head means;

an induction coil surrounding each bar;

said bars being operable to induce a current in a respective one of said coils during movement of said bars therethrough;

the induction coils being interconnected for causing a subtraction of currents induced therein by movement of the bars in the same direction and an addition of currents induced therein by movement of the bars in opposite directions.

7. Apparatus according to claim 1, wherein said control means is operatively connected to said measuring head means and said adjusting means such that the time between the, sensing of thickness and hardness fluctuations and the operation of said adjusting means is correlated to the speed of said strip material.

8. Apparatus according to claim 7 and further wherein said control means includestime delay means to compensate for fluctuations in the speed of the strip material.

9. Apparatus according to claim 1, wherein said strip working apparatus is reversible, and further wherein a measuring head assembly is positioned on each side of said strip working means.

10. Apparatus according to claim 1, wherein said strip working means comprises a rolling mill.

11. Apparatus according to claim 10, wherein said rolling mill includes at least one work roll;

and further wherein said adjusting means includes:

a backing roller engaging said work roll, said backing roller being mounted by an eccentric bearing having a toothed gear thereon;

a toothed rack connected between a pair of hydraulic cylinders and drivingly engaging said toothed gear; and

a valve connected between said control means and said hydraulic cylinders to direct fluid to one of said cylinders under the influence of said control means, to cause adjustment of said work roll.

12. Apparatus according to claim 10 wherein said rolling mill includes a pair of oppositely spaced work rolls, and further wherein said adjusting means includes hydraulically operated backing means engaging each of said work rolls.

13. Apparatus according to claim 10, wherein said rolling mill comprises part of a casting, rolling, milling, and finishing apparatus.

14. A method of measuring and working strip material comprising the steps of:

passing said strip material between a pair of oppositely positioned, displaceable measuring head means;

pressing each of said measuring head means against said sheet material with a force of .a magnitude adequate to cause sufiicient deformation of said strip material for sensing both thickness and hardness characteristics of said strip material;

causing said measuring head means to be displaceable in response to a change in counterpressure exerted by said strip material resulting from sensed thickness and hardness fluctuations;

detecting displacement of said measuring head means resulting from changes in said counterpressurc produced by thickness fluctuations and hardness fluctuations in said strip material; and

causing said detected displacement to operate an adjusting 5 means of a strip-working means positioned downstream of said measuring heads to adjust said strip-working means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3.665.743 'D t d May 30; 1972 Inventor(s) JOSEF FROHLING It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the title page of the patent, Item [30] the Foreign Application Priority Data should read as follows:

Signed and sealed this 6th day of February 1973.

(SEAL) Attost:

EDWARD M. FLTE'I'CIIIZR 'J R ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-IOSO (10-69) USCOMM DC 60376 P69 w u.s. covzmmzm PRINTING OFFICE: I969 o-36s-334 

1. A measuring and working apparatus for moving strip material comprising: a strip working means for working said strip material; an adjusting means operatively connected to said strip working means to adjust the latter in accordance with strip characteristics; a measuring head assembly positioned upstream of said strip working means for regulating the adjustment of said strip working means in response to fluctuations in the thickness and hardness characteristics of the strip material, said measuring head assembly comprising: a pair of oppositely positioned measuring head means mounted to engage opposite surfaces of said strip material; said measuring head means being mounted for displacement in a direction generally perpendicular to the direction of movement of said strip material; pressure means for urging the measuring head means into engagement with said strip material with a force of a magnitude adequate to cause sufficient deformation of said strip material for sensing both thickness and hardness characteristics of said strip material; said urged measuring head means being movable in response to a change in counterpressure exerted by said strip material resulting from sensed thickness and hardness characteristics thereof; and control means operatively associated with said measuring head means and said adjusting means for operating said adjusting means in response to said displacement of said pressured measuring head means due to changes in said counterpressure produced by thickness fluctuations and hardness fluctuations of said strip material sensed by said measuring head means.
 2. Apparatus according to claim 1 wherein the force exerted by said pressure means causes a deformation of said strip material within its elastic limit.
 3. Apparatus according to claim 1 wherein said pressure means includes hydraulically operated means.
 4. Apparatus according to claim 1 wherein each measuring head means includes a freely rotatable roller bearing against said strip material.
 5. Apparatus according to claim 4 wherein the surfaces of said rollers are cambered.
 6. Apparatus according to claim 1 wherein said control means comprises: a bar of magnetic material connected to each measuring head means for transmitting said displacement of each measuring head means; an induction coil surrounding each bar; said bars being operable to induce a current in a respective one of said coils during movement of said bars therethrough; the induction coils being interconnected for causing a subtraction of currents induced therein by movement of the bars in the same direction and an addition of currents induced therein by movement of the bars in opposite directions.
 7. Apparatus according to claim 1, wherein said control means is operatively connected to said measuring head means and said adjusting means such that the time between the sensing of thickness and hardness fluctuations and the operation of said adjusting means is correlated to the speed of said strip material.
 8. Apparatus according to claim 7 and further wherein said control means includes time delay means to compensate for fluctuations in the speed of the strip material.
 9. Apparatus according to claim 1, wherein said strip working apparatus is reversible, and further wherein a measuring head assembly is positioned on each side of said strip working means.
 10. Apparatus according to claim 1, wherein said strip working means comprises a rolling mill.
 11. Apparatus according to claim 10, wherein said rolling mill includes at least one work roll; and further wherein said adjusting means includes: a backing roller engaging said work roll, said backing roller being mounted by an eccentric bearing having a toothed gear thereon; a toothed rack connected between a pair of hydraulic cylinders and drivingly engaging said toothed gear; and a valve connected between said control means and said hydraulic cylinders to direct fluid to one of said cylinders under the influence of said control means, to cause adjustment of said work roll.
 12. Apparatus according to claim 10 wherein said rolling mill includes a pair oF oppositely spaced work rolls, and further wherein said adjusting means includes hydraulically operated backing means engaging each of said work rolls.
 13. Apparatus according to claim 10, wherein said rolling mill comprises part of a casting, rolling, milling, and finishing apparatus.
 14. A method of measuring and working strip material comprising the steps of: passing said strip material between a pair of oppositely positioned, displaceable measuring head means; pressing each of said measuring head means against said sheet material with a force of a magnitude adequate to cause sufficient deformation of said strip material for sensing both thickness and hardness characteristics of said strip material; causing said measuring head means to be displaceable in response to a change in counterpressure exerted by said strip material resulting from sensed thickness and hardness fluctuations; detecting displacement of said measuring head means resulting from changes in said counterpressure produced by thickness fluctuations and hardness fluctuations in said strip material; and causing said detected displacement to operate an adjusting means of a strip-working means positioned downstream of said measuring heads to adjust said strip-working means. 